Single-walled carbon nanotubes (SWNTs) have attracted attention because of their unique electronic and mechanical properties. They have the highest measured tensile strength, are flexible, lightweight, and exhibit low power consumption while retaining high on/off ratios in electronic materials. These seamless tubes of graphene are typically micrometers long and one nanometer in diameter. However, unlike graphene, SWNTs exist as either semi-conductive or metallic conductors due to quantum confinement effects resulting from their curvature. Therefore, there is particular interest in using SWNTs for electronic applications.
Despite their great potential, the widespread use of SWNTs in electronic materials remains stalled by issues with unbundling and purifying them in order to obtain much greater precision over their electronic properties. This is important because, regardless of the growth method, as-produced (AP) grade SWNT soot is a mixture of SWNTs, metal catalyst nanoparticles, and amorphous carbon. The majority of existing purification methods involve oxidizing SWNT soot in strong acids and/or gases. These types of treatments remove metal catalyst nanoparticles and amorphous carbon, but significantly damage the SWNTs and increase their electrical resistance. In addition, use of SWNTs in electronic materials will require addressing a major barrier—the reduction of their high sheet resistance (R).